Methods and apparatus for completing unconsolidated lateral well bores

ABSTRACT

Improved methods and apparatus for completing unconsolidated subterranean zones penetrated by well bores are provided. The methods basically comprise the steps of placing a slotted pipe having openings formed therein which vary in size or in the number of openings along the length of the slotted pipe or both in the subterranean zone, isolating the annulus between the slotted pipe and the well bore and injecting particulate material into the annulus whereby the particulate material is uniformly packed therein.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to improved methods and apparatusfor completing unconsolidated lateral well bores.

[0003] 2. Description of the Prior Art

[0004] Lateral well bores, i.e., well bores that are drilledhorizontally or substantially in a horizontal direction from a verticalor substantially vertical primary well bore are often completed inunconsolidated formations containing loose and incompetent fines andsand which migrate with fluids produced from the formations. Thepresence of formation fines and sand in the produced fluids isundesirable in that the particles abrade tubular goods, producingequipment, pumps and the like and reduce the fluid productioncapabilities of the formations.

[0005] In order to terminate or reduce the presence of formation finesand sand in produced fluids, completions utilizing gravel packs areoften utilized. In a typical gravel pack completion, a screen is placedin the well bore and positioned within the unconsolidated subterraneanzone which is to be completed. The screen is connected to a tool whichincludes a production packer and a crossover and the tool is in turnconnected to a work or production pipe string. A particulate materialwhich is usually graded sand, often referred to in the art as gravel, ispumped in a slurry down the work or production pipe string and throughthe crossover whereby it flows into the annulus between the screen andthe well bore. The liquid forming the slurry leaks off into thesubterranean zone and/or through the screen which is sized to preventthe gravel in the slurry from flowing therethrough. As a result, thegravel is deposited in the annulus around the screen whereby it forms agravel pack. The size of the gravel in the gravel pack is selected suchthat it prevents formation fines and sand from flowing into the wellbore with produced fluids.

[0006] Gravel packs have also been formed in well bores using slottedpipes. The gravel is placed in the annulus between a slotted pipe andthe walls of the well bore as well as within the pipe. The gravel isusually coated with a hardenable resin composition which consolidatesthe gravel into a hard permeable pack. Thereafter, the gravel depositedwithin the slotted pipe can be drilled out of the slotted pipe or leftin the slotted pipe as desired.

[0007] Another more recent gravel pack procedure which prevents theformation of gravel bridges in the annulus between the walls of a wellbore and a screen or slotted pipe has been developed and utilizedsuccessfully. Gravel bridges occur as the result of non-uniform gravelpacking in the annulus due to the loss of carrier liquid from the gravelslurry into high permeability portions of the subterranean zone. Thegravel bridges occur before all of the gravel has been placed and theyblock further flow of the slurry and gravel through the annulus whichleaves voids in the annulus. When the well is placed on production, theflow of produced fluids is concentrated through the voids in the gravelpack which soon causes the migration of fines and sand with the producedfluids.

[0008] Gravel bridges have heretofore been prevented by utilizing aslotted pipe, i.e., a pipe with openings formed therein, with a sandscreen disposed within the slotted pipe. The gravel slurry is injectedinto the annulus between the slotted pipe and the walls of the well boreand between the slotted pipe and the sand screen. This arrangementallows the gravel slurry to flow around gravel bridges and depositgravel in voids produced.

[0009] Another problem very often encountered in the completion oflateral well bores involves unequal production of formation fluids alongthe length of the lateral well bore. Lateral well bores are utilized insubterranean formation producing zones to increase the area of well borepenetration in the subterranean zones to thereby increase hydrocarbonproduction. However, the portion of a subterranean formation penetratedby the heel of a lateral well bore often experiences higher draw-downpressure than the portion of the well bore closest to the toe. The term“heel” refers to the portion of the lateral well bore where the wellbore begins its curvature to horizontal and the term “toe” refers to theend portion of the lateral well bore. As a result of the higherdraw-down pressure, higher hydrocarbon production rates result from theheel than from the toe. The higher hydrocarbon production rates from theheel can bring about early water break through or early gas breakthrough. This in turn can cause the full production potential of the toesection to never be realized.

[0010] Thus, there are needs for improved methods and apparatus forcompleting lateral wells bores in unconsolidated subterranean zonesusing gravel packs whereby gravel bridges are prevented and producedformation fluids are caused to flow into the slotted pipe atsubstantially equal rates over the length of the slotted pipe.

SUMMARY OF THE INVENTION

[0011] The present invention provides improved methods and apparatus forcompleting unconsolidated subterranean zones subject to migration offormation fines and sand with produced formation fluids penetrated bylateral well bores which meet the needs described above and overcome thedeficiencies of the prior art. The improved methods basically comprisethe steps of placing a slotted pipe in the lateral well bore havingopenings formed therein through which produced formation fluids flow.The openings vary in size or vary in the number of the openings alongthe length of the slotted pipe or both so that the produced formationfluids flow into the slotted pipe at substantially equal flow rates overthe length of the slotted pipe. The annulus between the slotted pipe andthe well bore is isolated and particulate material is injected into theannulus whereby the particulate material is uniformly packed in theannulus and in the interior of the slotted pipe so that the migration offormation fines and sand with produced formation fluids is prevented.

[0012] The lateral well bore can be cased with perforations formedtherein or completed open-hole and the particulate material ispreferably graded sand. The particulate material utilized is preferablycoated with a hardenable resin composition which hardens andconsolidates the particulate material into a hard permeable uniformmass. Once the hardenable resin has hardened whereby the particulatematerial is consolidated into a hard permeable pack in the annulusbetween the slotted pipe and the well bore as well as in the interior ofthe slotted pipe, at least a portion of the hard permeable mass withinthe interior of the slotted pipe can be drilled out if desired.

[0013] Another method of the present invention is comprised of thefollowing steps. A slotted pipe is placed in the lateral well borehaving openings formed therein through which the produced formationfluids flow and having an internal sand screen disposed therein. Theslotted pipe includes openings that vary in size or vary in the numberof openings along the length of the slotted pipe or both so that theproduced formation fluids flow into the slotted pipe at substantiallyequal flow rates over the length of the slotted pipe. The annulusbetween the slotted pipe and the well bore and the annulus between thesand screen and the slotted pipe are isolated. Thereafter, particulatematerial is injected into the annulus between the slotted pipe and thewell bore and the annulus between the slotted pipe and the sand screenwhereby the particulate material is uniformly packed in the annulusesand the migration of formation fines and sand with produced fluids isprevented.

[0014] The objects, features and advantages of the present inventionwill be readily apparent to those skilled in the art upon a reading ofthe description of preferred embodiments which follows when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a side cross-sectional view of a lateral open-hole wellbore penetrating an unconsolidated subterranean producing zone having aslotted pipe, a production packer and a crossover connected to aproduction string disposed therein. The drawing illustrates theplacement of gravel between the well bore and the slotted pipe andbetween the slotted pipe and the sand screen.

[0016]FIG. 2 is a side cross-sectional view of the lateral well bore,the slotted pipe with an internal sand screen, the production packer andthe cross-over of FIG. 1 after the gravel has been placed and producedfluids are flowing to the surface.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0017] The present invention provides improved methods and apparatus forcompleting an unconsolidated subterranean zone subject to the migrationof formation fines and sand penetrated by a lateral well bore havingunequal produced formation fluid flow rates over the length of the wellbore. The term “lateral well bore” is used herein to mean the portion ofa well bore in an unconsolidated subterranean producing zone to becompleted which is substantially horizontal or at an angle from verticalin the range of from about 65° to about 105°. The term “slotted pipe” isused herein to mean pipe which includes slots, holes or other shapedopenings therein.

[0018] Referring now to the drawings, the improved apparatus of thepresent invention is illustrated disposed in an open hole lateral wellbore 2. The lateral well bore 2 is illustrated extending into anunconsolidated subterranean zone 4 from a cased and cemented well bore 6which extends to the surface. A slotted pipe 8 having a plurality ofopenings 24 therein is disposed in the lateral well bore 2 whereby anannulus 22 is formed between the walls of the well bore 2 and theslotted pipe 8. A sand screen 10 is disposed within the slotted pipe 8in a manner whereby an annulus 12 is formed between the slotted pipe 8and the sand screen 10. The slotted pipe 8 and sand screen 10 areconnected to a removable cross-over 14 which is in turn connected to aproduction or work string 16. A production packer 18 is connected to theslotted pipe 8 which is set within the casing 20 in the well bore 6. Aswill be described further hereinbelow, FIG. 1 illustrates the operationof the apparatus of this invention when a slurry of particulate materialis pumped into the annulus 12 between the slotted pipe 8 and the sandscreen 10 and into the annulus 22 between the slotted pipe 8 and thewalls of the well bore 2. FIG. 2 illustrates the apparatus of theinvention after the particulate material 26 has been packed into theannuluses 12 and 22 and the well is returned to production. The pack ofparticulate material 26 within the annuluses 12 and 22 filters out andprevents the migration of formation fines and sand with producedformation fluids that enter the well bore 2 from the unconsolidatedsubterranean zone 4.

[0019] As is understood by those skilled in the art, the removablecross-over 14 is a sub-assembly which allows fluids to follow a firstflow pattern whereby particulate material suspended in a slurry can bepacked in the annuluses 12 and 22 between the sand screen 10 and theslotted pipe 8 and between the slotted pipe 8 and the well bore 2. Thatis, as shown by the arrows in FIG. 1, the particulate materialsuspension flows from inside the production or work string 16 into theannulus between the sand screen 10 and the slotted pipe 8 and into theannulus between the slotted pipe 8 and the well bore 2 by way of portsin the cross-over 14. Simultaneously, fluid is allowed to flow frominside the sand screen 10 through the cross-over 14 to the other side ofthe packer 18 outside the production string. By pipe movement or otherprocedure, flow through the cross-over 14 can be changed to a secondflow pattern whereby fluid from inside the sand screen 10 flows directlyinto the production string.

[0020] As shown in the drawings, the slotted pipe 8 includes a pluralityof circular openings 24 formed therein through which the producedformation fluids flow. The openings 24 are of varying sizes extendingover the length of the slotted pipe 8. That is, the openings 24 aresmall at the inlet end of the slotted pipe 8 adjacent to the heelportion of the well bore 2 (identified in the drawings by the numeral30) and increase in size over the length of the slotted pipe to the toeportion of the well bore (identified in the drawings by the numeral 32).The openings 24 can be of varying size over the length of the slottedpipe 8 as shown in the drawings or the openings 24 can be of the samesize over the length of the slotted pipe 8 with the number of openingsincreasing or otherwise varying over the length of the slotted pipe 8.

[0021] As is well known and generally the case, the production ofproduced hydrocarbon fluids near the heel portion of a lateral well borehave a high flow rate while the production of hydrocarbons near the toeof the well bore are much lower. This unequal production of hydrocarbonsfrom the heel to the toe often leads to premature gas or water coning atthe heel portion of the well bore, i.e., the area of high flow rate,which reduces the total volume of hydrocarbons that can be produced fromthe well bore. In accordance with the present invention, this problem isprevented by varying the size or the number of openings 24 over thelength of the slotted pipe 8 whereby the flow rate of produced fluidsinto the slotted pipe 8 from the lateral well bore is distributedsubstantially equally over the length of the slotted pipe 8. Therequired sizes of the openings 24 or the number of the same sizeopenings 24 allocated over the length of the slotted pipe 8 isdetermined by production tests conducted in the lateral well bore priorto the placement of the slotted pipe 8 and related apparatus in the wellbore or by estimation of the pressure drop from the heel of the wellbore to the toe of the well bore. Depending on the particular lateralwell bore involved and the particular areas of high or low formationfluid production, the sizes and/or number of openings required in theslotted pipe 8 to produce substantially equal flow rates of producedfluids into the slotted pipe 8 over its length are determined. A slottedpipe 8 with those openings is then placed in the lateral well bore alongwith the other apparatus required.

[0022] Referring again to FIGS. 1 and 2, the methods of the presentinvention for completing the well bore 2 in the unconsolidatedsubterranean zone 4 are as follows. The slotted pipe 8 containing theopenings 24 required to produce equal produced fluid flow over thelength of the slotted pipe 8 with the sand screen 10 therein is placedin the well bore 2. As will be understood, the sand screen can beomitted if the procedure described above is utilized whereby theparticulate material placed in the well bore is consolidated into apermeable pack or is otherwise prevented from flowing out of the wellbore with produced formation fluids. The annulus 22 between the slottedpipe 8 and the walls of the well bore 2 as well as the annulus betweenthe sand screen 10 and the slotted pipe 8 are isolated by setting thepacker 18. Thereafter, a slurry of particulate material is injected intothe annulus 12 between the sand screen 10 and the slotted pipe 8 andinto the annulus 22 between the walls of the well bore 2 and the slottedpipe 8. Because the particulate material slurry is free to flow throughthe openings 24 as well as the open end of the slotted pipe 8, theparticulate material is uniformly packed into the annulus 22 between thewell bore 2 and slotted pipe 8 and into the annulus 12 between the sandscreen 10 and the slotted pipe 8. The pack of particulate material 26formed filters out and prevents the migration of formation fines andsand with fluids produced into the well bore 2 from the subterraneanzone 4. The methods and apparatus of this invention are particularlysuitable and beneficial in forming gravel packs in long-interval lateralwells without the formation of sand bridges.

[0023] The particulate gravel material utilized in accordance with thepresent invention is generally of a size such that formation fines andsand that migrate with produced fluids are prevented from beingproduced. Various kinds of particulate gravel materials can be utilizedincluding graded sand, bauxite, ceramic materials, glass materials,polymer beads and the like. Generally the gravel particles have a sizein the range of from about 2 to about 400 mesh, U.S. Sieve Series. Thepreferred particulate gravel material is graded sand having a particlesize in the range of from about 10 to about 70 mesh, U.S. Sieve Series.Preferred sand particle size distribution ranges are one or more of10-20 mesh, 20-40 mesh, 40-60 mesh or 50-70 mesh, depending on aparticular size and distribution of formation solids to be screened outby the particulate gravel material.

[0024] As mentioned, the particulate gravel material can be coated witha hardenable resin composition. After the hardenable resin compositioncoated gravel is placed in the well bore, the hardenable resincomposition hardens and consolidates the gravel into a hard permeablemass. A variety of resin compositions are well known to those skilled inthe art as is their use for consolidating gravel material into hardpermeable masses. Examples of hardenable organic resins which aresuitable for use in accordance with this invention are novolac resins,polyepoxide resins, polyester resins, phenol-aldehyde resins,urea-aldehyde resins, furan resins, urethane resins, and mixtures ofsuch resins. These resins are available at various viscosities dependingupon the molecular weights of the resins. The resin or mixture of resinsutilized is generally diluted with a diluent. For example, polyepoxideresins can be diluted with methanol, butanol, dipropylene glycol methylether or dipropylene glycol dimethyl ether; whereas furan or phenolicresins can be diluted with phenols, formaldehydes, furfuryl alcohol,furfural or 2-butoxy ethanol. Also, silane coupling agents are generallyutilized in the hardenable resin compositions to promote coupling oradhesion to sand or other similar particulate gravel materials.Particularly suitable coupling agents are aminosilane compounds ormixtures of such compounds. A preferred coupling agent isN-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane. The hardenableresin composition used is caused to harden by allowing it to be heatedin the formation or by contacting it with a hardening agent. When ahardening agent is utilized, it can be included in the resincomposition. Examples of suitable internal hardening agents forpolyepoxide resins include, but are not limited to, amines and amides,preferably 2-ethyl 4-methyl imidazole and 4,4′-diaminodiphenyl sulfone.The suitable internal hardening agents for resin compositions containingfuran resin, phenol aldehyde resin or urea-aldehyde resin include, butare not limited to, hexachloroacetone, 1,1,3-trichlorotrifluoroacetone,benzotrichloride, benzylchloride and benzalchloride. The hardenableresin compositions can also include other components such assurfactants, dispersants, esters and other additives which are wellknown to those skilled in the art.

[0025] When particulate gravel material coated with a hardenable resincomposition is utilized, the sand screen disposed within theslotted-pipe can be eliminated. When the sand screen is not utilized,resin composition coated particulate material is injected into theannulus between the walls of the well bore and the slotted pipe as wellas into the interior of the slotted pipe. After the hardenable resincomposition coated proppant has hardened into a strong permeable packwithin the annulus and within the slotted pipe, all or a portion of theconsolidated proppant can be removed from the interior of the slottedpipe if desired.

[0026] When a sand screen within the slotted pipe is utilized asillustrated in the drawings, the sand screen prevents the proppantmaterial from flowing out of the well bore with produced fluids. Inaddition to the sand screen, the particulate material can also be coatedwith a hardenable resin composition whereby the particulate material isconsolidated into a strong permeable pack.

[0027] The particulate gravel material carrier liquid utilized can beany of the various viscous carrier liquids utilized heretofore includinggelled water, oil based liquids, foams or emulsions. The most commoncarrier liquid utilized heretofore which is also preferred for use inaccordance with this invention is comprised of an aqueous liquid such asfresh water or salt water combined with a gelling agent for increasingthe viscosity of the carrier liquid. The increased viscosity reducesfluid loss and allows the carrier liquid to transport significantconcentrations of particulate gravel material into the subterranean zoneto be completed.

[0028] A variety of gelling agents have been utilized includinghydratable polymers which contain one or more functional groups such ashydroxyl, cis-hydroxyl, carboxyl, sulfate, sulfonate, amino or amide.Particularly useful such polymers are polysaccharides and derivativesthereof which contain one or more of the monosaccharide units galactose,mannose, glucoside, glucose, xylose, arabinose, fructose glucuronic acidor pyranosyl sulfate. Various natural hydratable polymers contain theforegoing functional groups and units including guar gum and derivativesthereof, cellulose and derivatives thereof and the like. Hydratablesynthetic polymers and copolymers which contain the above mentionedfunctional groups can also be utilized including polyacrylate,polymethylacrylate, polyacrylamide and the like.

[0029] Particularly preferred hydratable polymers which yield highviscosities upon hydration at relatively low concentrations are guar gumand guar derivatives such as hydroxypropylguar and carboxymethylguar andcellulose derivatives such as hydroxyethylcellulose,carboxymethylcellulose and the like.

[0030] The viscosities of aqueous polymer solutions of the typesdescribed above can be increased by combining cross-linking agents withthe polymer solutions. Examples of cross-linking agents which can beutilized are multivalent metal salts, alkali metal borates, borax, boricacid and other boron compounds. The gelled or gelled and cross-linkedcarrier liquids can also include gel breakers such as those of theenzyme type, the oxidizing type or the acid buffer type which are wellknown to those skilled in the art. The gel breakers cause the viscouscarrier liquids to revert to thin fluids that can be produced back tothe surface after they have been utilized.

[0031] An improved method of the present invention for completing anunconsolidated subterranean zone subject to migration of formation finesand sand with produced formation fluids penetrated by a lateral wellbore comprises the steps of: (a) placing a slotted pipe in the lateralwell bore having openings formed therein through which the producedformation fluids flow, the openings varying in size or varying in thenumber of the openings along the length of the slotted pipe or both sothat the produced formation fluids flow into the slotted pipe atsubstantially equal flow rates over the length of the slotted pipe; (b)isolating the annulus between the slotted pipe and the well bore; and(c) injecting particulate material into the annulus between the slottedpipe and the well bore whereby the particulate material is uniformlypacked in the annulus and in the interior of the slotted pipe wherebythe migration of formation fines and sand with produced formation fluidsis prevented.

[0032] Another preferred method of this invention for completing anunconsolidated subterranean zone subject to migration of formation finesand sand with produced formation fluids penetrated by a lateral wellbore comprises the steps of: (a) placing a slotted pipe in the lateralwell bore having openings formed therein through which the producedformation fluids flow and having an internal sand screen disposedtherein, the openings in the slotted pipe varying in size or varying inthe number of the openings along the length of the slotted pipe or bothso that the produced formation fluids flow into the slotted pipe atsubstantially equal flow rates over the length of the slotted pipe; (b)isolating the annulus between the slotted pipe and the well bore and theannulus between the sand screen and the slotted pipe; and (c) injectingparticulate material into the annulus between the slotted pipe and thewell bore and the annulus between the slotted pipe and the sand screenwhereby the particulate material is uniformly packed in the annulusesand the migration of formation fines and sand with produced fluids isprevented.

[0033] A preferred apparatus of the present invention for completing anunconsolidated well bore comprises: a slotted pipe having openingsformed therein through which produced formation fluids flow, theopenings varying in size or varying in the number of the openings alongthe length of the slotted pipe or both so that the produced formationfluids flow into the slotted pipe at substantially equal flow rates overthe length of the slotted pipe; a removable cross-over adapted to beattached to a production or work string attached to the slotted pipe;and a production packer attached to the slotted pipe.

[0034] As mentioned above, the production packer and the cross-over areselectively operable from the surface. When operated, the packer is setand the cross-over changes from a first flow pattern to a second flowpattern.

[0035] As will be understood by those skilled in the art, instead of thesingle slotted pipe or single slotted pipe with a sand screen disposedtherein as described and claimed herein, other arrangements of one ormore slotted pipes of this invention having openings varying in size orvarying in the number of the openings along the length thereof, or both,with or without sand screens can be substituted therefore. Examples ofsuch other arrangements that can be utilized are described in detail inU.S. Pat. No. 6,516,881B2 issued to Hailey, Jr. on Feb. 11, 2003 and inU.S. Pat. No. 6,516,882B2 issued to McGregor, et al. on Feb. 11, 2003,which are incorporated in their entireties herein by reference thereto.

[0036] Thus, the present invention is well adapted to carry out theobjects and attain the ends and advantages mentioned as well as thosewhich are inherent therein. While numerous changes can be made by thoseskilled in the art, such changes are encompassed within the spirit ofthis invention as defined by the appended claims.

What is claimed is:
 1. An improved method of completing anunconsolidated subterranean zone subject to migration of formation finesand sand with produced formation fluids penetrated by a lateral wellbore comprising the steps of: (a) placing a slotted pipe in said lateralwell bore having openings formed therein through which said producedformation fluids flow, said openings varying in size or varying in thenumber of said openings along the length of said slotted pipe or both sothat said produced formation fluids flow into said slotted pipe atsubstantially equal flow rates over the length of said slotted pipe; (b)isolating the annulus between said slotted pipe and said well bore; and(c) injecting particulate material into said annulus between saidslotted pipe and said well bore whereby said particulate material isuniformly packed in said annulus and in the interior of said slottedpipe whereby the migration of formation fines and sand with producedformation fluids is prevented.
 2. The method of claim 1 wherein saidwell bore in said subterranean zone is open-hole.
 3. The method of claim1 wherein said particulate material is graded sand.
 4. The method ofclaim 1 wherein said particulate material is coated with a hardenableresin composition which hardens and consolidates said particulatematerial into a hard permeable uniform mass.
 5. The method of claim 4which further comprises the step of drilling at least a portion of saidhard permeable mass of particulate material out of the interior of saidslotted pipe.
 6. The method of claim 1 wherein said annulus between saidslotted pipe and said lateral well bore is isolated in accordance withstep (b) by setting a packer in said well bore.
 7. The method of claim 3which further comprises an internal sand screen disposed within saidslotted pipe which forms an annulus between said sand screen and saidslotted pipe which is also isolated.
 8. The method of claim 7 whereinsaid particulate material is also injected into said annulus betweensaid sand screen and said slotted pipe.
 9. The method of claim 8 whereinsaid particulate material is coated with a hardenable resin compositionwhich hardens and consolidates said particulate material into a hardpermeable uniform mass.
 10. The method of claim 3 wherein said gradedsand has a particle size in the range of from about 10 to about 70 mesh,U.S. Sieve Series.
 11. An improved method of completing anunconsolidated subterranean zone subject to migration of formation finesand sand with produced formation fluids penetrated by a lateral wellbore comprising the steps of: (a) placing a slotted pipe in said lateralwell bore having openings formed therein through which said producedformation fluids flow and having an internal sand screen disposedtherein, said openings in said slotted pipe varying in size or varyingin the number of said openings along the length of said slotted pipe orboth so that said produced formation fluids flow into said slotted pipeat substantially equal flow rates over the length of said slotted pipe;(b) isolating the annulus between said slotted pipe and said well boreand the annulus between said sand screen and said slotted pipe; and (c)injecting particulate material into said annulus between said slottedpipe and said well bore and said annulus between said slotted pipe andsaid sand screen whereby said particulate material is uniformly packedin said annuluses and the migration of formation fines and sand withproduced fluids is prevented.
 12. The method of claim 11 wherein saidwell bore in said subterranean zone is open-hole.
 13. The method ofclaim 11 wherein said particulate material is graded sand.
 14. Themethod of claim 11 wherein said particulate material is coated with ahardenable resin composition which hardens and consolidates saidparticulate material into a hard permeable uniform mass.
 15. The methodof claim 11 wherein said annulus between said slotted pipe and said wellbore and said annulus between said sand screen and said slotted pipe areisolated in accordance with step (b) by setting a packer in said wellbore.
 16. The method of claim 13 wherein said graded sand has a particlesize in the range of from about 10 to about 70 mesh, U.S. Sieve Series.17. An apparatus for completing an unconsolidated well bore comprising:a slotted pipe having openings formed therein through which producedformation fluids flow, said openings varying in size or varying in thenumber of said openings along the length of said slotted pipe or both sothat said produced formation fluids flow into said slotted pipe atsubstantially equal flow rates over the length of said slotted pipe; aremovable cross-over adapted to be attached to a production or workstring attached to said slotted pipe; and a production packer attachedto said slotted pipe.
 18. The apparatus of claim 17 which furthercomprises a sand screen disposed within said slotted pipe and attachedthereto.
 19. The apparatus of claim 17 wherein said production packer isselectively operable from the surface when located in said well bore.20. The apparatus of claim 17 wherein said cross-over is selectivelyoperable from the surface when located in said well bore to change froma first flow pattern to a second flow pattern.